99 Accord Lx 4cyl....has weak heater
 

Howd'y Folks

My wifes 99 accord blows luke warm air....I've been over all the normal stuff.
Replace the water pump, heater control valve, dash knob, thermastat (I put in a 180 deg) should work. Flushed engine, rad, & heater core. It seems to me that there is not enough adjustment at the heater control valve, the one by the firewall to completely open the valve. I have clamped the cable sheath as far forward as it will go, and still the new valve arm is not in the right position for the valve to be open all the way. Sooo...what I'm looking for here is the location of the other end of the cable under the dash...from what I'm told there is another clamp on the sheath that will help refine the adjustment at the control vale in the engine compartment. With the key in the on position I can hear what sounds like a servo or a stepping motor advanceing when I turn the heater knob on the dash, but still, I cannot find the darn thing.. any ideas?

Re: 99 Accord Lx 4cyl....has weak heater
 

Manual or auto temp control? Just for grins....if you pull the cable from the valve and manually open the valve, what does the heat do?

Re: 99 Accord Lx 4cyl....has weak heater
 

Manual temp control....If I fully open the valve the heater works very good. I found the other end of the cable under the dash (center) there is just no way the get at the darn thing without removing most of the dash. I'll live with what I have or I might try to change the position of the heater valve under the hood. Thanks..
Bligh

Re: 99 Accord Lx 4cyl....has weak heater
 

Bligh

I fight the same exact issue. The other end to the water valve cable goes by the passenger side. The servo motor location is right behind the center consol. If you remove the floor carpet you will get to see where exactly the cable clamps (similar to how its done for water valve). My motor works well and i even have disconnected the cable at the valve and leave the valve right open still no change. I have new rad, thermostat original from honda, water valve, coolant flushed using garden hose in -15c - two times. At last i tried lifting up the front a little before refilling the coolant and then have the fan come on atleast two times and close radiator cap. This seems to have helped a little. It will only blow hot when accelerating...but at idle it gets near cold. I do not suspect the heater core itself but its a heck of a job to remove the dash. Let me know how you make out and good luck :)

Re: 99 Accord Lx 4cyl....has weak heater
 

Thanks for your reply....one of the last things I did was to flush the heater core with muratic acid....a 50% dilluted solution. The heater core reacted like it was full of stuff that the acid reacted with....(muratic acid will not harm good metal) I've used this method before on Marine engines to clean the heat exchangers with good results. It did make a difference but sure as heck is not like a new car. I"ve decided to live with it the way it is. With 210 thousand miles on it...I'll give it this one. Thanks again
Bligh

Re: 99 Accord Lx 4cyl....has weak heater
 

Did you reverse flush the heater core? I was told that it should get nice and hot after a reverse flush of the heater core. Otherwise, there might be some gunks inside the heater core tubes which doesn't allow much of coolant flow.

Re: 99 Accord Lx 4cyl....has weak heater
 

Thanks for your reply...yes, I did try that with a garden hose. I had what I thought to be good water flow in both directions, the water was clean and looked as though there were no obstructions within the heater core. I've thought about installing a 190deg. thermostat....the book calls for 180deg. I thought better of that believing that 180deg is plenty hot enough to generate hot air. I must admit I'm at my wit's end with this one.
Winter is nearly over and the heater does blow mildly warm air...the car just passed NJ State inspection, so I'm good to go for another two years. As was suggested to me, in this thread, try running the car with the heater valve set manually in the max flow position . I did that and the heat was better, but only marginally so. I'm gonna let this one go, and consider that only a new heater core would sove this problem and that ain't gonna happen....So, thanks again.
Bligh